/*
 * Copyright (C) 2007 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.inject.internal;

import static com.google.common.base.Preconditions.checkState;
import static com.google.inject.internal.Annotations.findScopeAnnotation;

import com.google.common.base.Objects;
import com.google.common.collect.ImmutableSet;
import com.google.inject.Binder;
import com.google.inject.ConfigurationException;
import com.google.inject.Inject;
import com.google.inject.Key;
import com.google.inject.TypeLiteral;
import com.google.inject.internal.util.Classes;
import com.google.inject.spi.BindingTargetVisitor;
import com.google.inject.spi.ConstructorBinding;
import com.google.inject.spi.Dependency;
import com.google.inject.spi.InjectionPoint;

import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.List;
import java.util.Map;
import java.util.Set;

final class ConstructorBindingImpl<T> extends BindingImpl<T> implements ConstructorBinding<T>, DelayedInitialize {

    private final Factory<T> factory;
    private final InjectionPoint constructorInjectionPoint;

    private ConstructorBindingImpl(InjectorImpl injector, Key<T> key, Object source, InternalFactory<? extends T> scopedFactory, Scoping scoping, Factory<T> factory, InjectionPoint constructorInjectionPoint) {
        super(injector, key, source, scopedFactory, scoping);
        this.factory = factory;
        this.constructorInjectionPoint = constructorInjectionPoint;
    }

    public ConstructorBindingImpl(Key<T> key, Object source, Scoping scoping, InjectionPoint constructorInjectionPoint, Set<InjectionPoint> injectionPoints) {
        super(source, key, scoping);
        this.factory = new Factory<T>(false, key);
        ConstructionProxy<T> constructionProxy = new DefaultConstructionProxyFactory<T>(constructorInjectionPoint).create();
        this.constructorInjectionPoint = constructorInjectionPoint;
        factory.constructorInjector = new ConstructorInjector<T>(injectionPoints, constructionProxy, null, null);
    }

    /**
     * 
     * @param constructorInjector the constructor to use, or {@code null} to use the default.
     * @param failIfNotLinked true if this ConstructorBindingImpl's InternalFactory should
     *                             only succeed if retrieved from a linked binding
     */
    static <T> ConstructorBindingImpl<T> create(InjectorImpl injector, Key<T> key, InjectionPoint constructorInjector, Object source, Scoping scoping, Errors errors, boolean failIfNotLinked, boolean failIfNotExplicit) throws ErrorsException {
        int numErrors = errors.size();

        @SuppressWarnings("unchecked") // constructorBinding guarantees type is consistent
        Class<? super T> rawType = constructorInjector == null ? key.getTypeLiteral().getRawType() : (Class) constructorInjector.getDeclaringType().getRawType();

        // We can't inject abstract classes.
        if (Modifier.isAbstract(rawType.getModifiers())) {
            errors.missingImplementation(key);
        }

        // Error: Inner class.
        if (Classes.isInnerClass(rawType)) {
            errors.cannotInjectInnerClass(rawType);
        }

        errors.throwIfNewErrors(numErrors);

        // Find a constructor annotated @Inject
        if (constructorInjector == null) {
            try {
                constructorInjector = InjectionPoint.forConstructorOf(key.getTypeLiteral());
                if (failIfNotExplicit && !hasAtInject((Constructor) constructorInjector.getMember())) {
                    errors.atInjectRequired(rawType);
                }
            } catch (ConfigurationException e) {
                throw errors.merge(e.getErrorMessages()).toException();
            }
        }

        // if no scope is specified, look for a scoping annotation on the concrete class
        if (!scoping.isExplicitlyScoped()) {
            Class<?> annotatedType = constructorInjector.getMember().getDeclaringClass();
            Class<? extends Annotation> scopeAnnotation = findScopeAnnotation(errors, annotatedType);
            if (scopeAnnotation != null) {
                scoping = Scoping.makeInjectable(Scoping.forAnnotation(scopeAnnotation), injector, errors.withSource(rawType));
            }
        }

        errors.throwIfNewErrors(numErrors);

        Factory<T> factoryFactory = new Factory<T>(failIfNotLinked, key);
        InternalFactory<? extends T> scopedFactory = Scoping.scope(key, injector, factoryFactory, source, scoping);

        return new ConstructorBindingImpl<T>(injector, key, source, scopedFactory, scoping, factoryFactory, constructorInjector);
    }

    /** Returns true if the inject annotation is on the constructor. */
    private static boolean hasAtInject(Constructor cxtor) {
        return cxtor.isAnnotationPresent(Inject.class) || cxtor.isAnnotationPresent(javax.inject.Inject.class);
    }

    @SuppressWarnings("unchecked") // the result type always agrees with the ConstructorInjector type
    public void initialize(InjectorImpl injector, Errors errors) throws ErrorsException {
        factory.constructorInjector = (ConstructorInjector<T>) injector.constructors.get(constructorInjectionPoint, errors);
        factory.provisionCallback = injector.provisionListenerStore.get(this);
    }

    /** True if this binding has been initialized and is ready for use. */
    boolean isInitialized() {
        return factory.constructorInjector != null;
    }

    /** Returns an injection point that can be used to clean up the constructor store. */
    InjectionPoint getInternalConstructor() {
        if (factory.constructorInjector != null) {
            return factory.constructorInjector.getConstructionProxy().getInjectionPoint();
        } else {
            return constructorInjectionPoint;
        }
    }

    /** Returns a set of dependencies that can be iterated over to clean up stray JIT bindings. */
    Set<Dependency<?>> getInternalDependencies() {
        ImmutableSet.Builder<InjectionPoint> builder = ImmutableSet.builder();
        if (factory.constructorInjector == null) {
            builder.add(constructorInjectionPoint);
            // If the below throws, it's OK -- we just ignore those dependencies, because no one
            // could have used them anyway.
            try {
                builder.addAll(InjectionPoint.forInstanceMethodsAndFields(constructorInjectionPoint.getDeclaringType()));
            } catch (ConfigurationException ignored) {
            }
        } else {
            builder.add(getConstructor()).addAll(getInjectableMembers());
        }

        return Dependency.forInjectionPoints(builder.build());
    }

    public <V> V acceptTargetVisitor(BindingTargetVisitor<? super T, V> visitor) {
        checkState(factory.constructorInjector != null, "not initialized");
        return visitor.visit(this);
    }

    public InjectionPoint getConstructor() {
        checkState(factory.constructorInjector != null, "Binding is not ready");
        return factory.constructorInjector.getConstructionProxy().getInjectionPoint();
    }

    public Set<InjectionPoint> getInjectableMembers() {
        checkState(factory.constructorInjector != null, "Binding is not ready");
        return factory.constructorInjector.getInjectableMembers();
    }

    /*if[AOP]*/
    public Map<Method, List<org.aopalliance.intercept.MethodInterceptor>> getMethodInterceptors() {
        checkState(factory.constructorInjector != null, "Binding is not ready");
        return factory.constructorInjector.getConstructionProxy().getMethodInterceptors();
    }
    /*end[AOP]*/

    public Set<Dependency<?>> getDependencies() {
        return Dependency.forInjectionPoints(new ImmutableSet.Builder<InjectionPoint>().add(getConstructor()).addAll(getInjectableMembers()).build());
    }

    @Override
    protected BindingImpl<T> withScoping(Scoping scoping) {
        return new ConstructorBindingImpl<T>(null, getKey(), getSource(), factory, scoping, factory, constructorInjectionPoint);
    }

    @Override
    protected BindingImpl<T> withKey(Key<T> key) {
        return new ConstructorBindingImpl<T>(null, key, getSource(), factory, getScoping(), factory, constructorInjectionPoint);
    }

    @SuppressWarnings("unchecked") // the raw constructor member and declaring type always agree
    public void applyTo(Binder binder) {
        InjectionPoint constructor = getConstructor();
        getScoping().applyTo(binder.withSource(getSource()).bind(getKey()).toConstructor((Constructor) getConstructor().getMember(), (TypeLiteral) constructor.getDeclaringType()));
    }

    @Override
    public String toString() {
        return Objects.toStringHelper(ConstructorBinding.class).add("key", getKey()).add("source", getSource()).add("scope", getScoping()).toString();
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof ConstructorBindingImpl) {
            ConstructorBindingImpl<?> o = (ConstructorBindingImpl<?>) obj;
            return getKey().equals(o.getKey()) && getScoping().equals(o.getScoping()) && Objects.equal(constructorInjectionPoint, o.constructorInjectionPoint);
        } else {
            return false;
        }
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(getKey(), getScoping(), constructorInjectionPoint);
    }

    private static class Factory<T> implements InternalFactory<T> {
        private final boolean failIfNotLinked;
        private final Key<?> key;
        private ConstructorInjector<T> constructorInjector;
        private ProvisionListenerStackCallback<T> provisionCallback;

        Factory(boolean failIfNotLinked, Key<?> key) {
            this.failIfNotLinked = failIfNotLinked;
            this.key = key;
        }

        @SuppressWarnings("unchecked")
        public T get(Errors errors, InternalContext context, Dependency<?> dependency, boolean linked) throws ErrorsException {
            checkState(constructorInjector != null, "Constructor not ready");

            if (failIfNotLinked && !linked) {
                throw errors.jitDisabled(key).toException();
            }

            // This may not actually be safe because it could return a super type of T (if that's all the
            // client needs), but it should be OK in practice thanks to the wonders of erasure.
            return (T) constructorInjector.construct(errors, context, dependency.getKey().getTypeLiteral().getRawType(), provisionCallback);
        }
    }
}
